Friedel-Crafts alkylation between chalcone epoxides and heteroarenes induced by triarylaminium salt

Triarylaminium salt was disclosed as a highly efficient nonmetallic initiator for the Friedel Crafts reaction between chalcone epoxides and heteroarenes to construct a series of complex beta-heteroaryl alpha-ketols in mild conditions and with good yields. Chalcone epoxides were presented as valuable halogen-free pre-electrophile in Friedel-Crafts alkylation through the formation of the stabilized benzylic cation intermediates. A plausible radical cation chain mechanism was also proposed. (C) 2011 Elsevier Ltd. All rights reserved.